DSP56002RC40 Motorola Inc, DSP56002RC40 Datasheet - Page 101

• Manufacturer Part Number: DSP56002RC40
• Description: 24-BIT DIGITAL SIGNAL PROCESSOR
• Manufacturer: Motorola Inc

HEAT DISSIPATION
MOTOROLA
Equation 1:
Equation 2:
An estimation of the chip junction temperature, T
equation:
Where:
T
R
P
Historically, thermal resistance has been expressed as the sum of a junction-to-case
thermal resistance and a case-to-ambient thermal resistance:
Where:
R
R
R
R
thermal environment to change the case-to-ambient thermal resistance, R
example, the user can change the air flow around the device, add a heat sink, change
the mounting arrangement on the Printed Circuit Board, or otherwise change the
thermal dissipation capability of the area surrounding the device on a Printed Circuit
Board. This model is most useful for ceramic packages with heat sinks; some 90% of
the heat flow is dissipated through the case to the heat sink and out to the ambient
environment. For ceramic packages, in situations where the heat flow is split between
a path to the case and an alternate path through the Printed Circuit Board, analysis of
the device thermal performance may need the additional modeling capability of a
system level thermal simulation tool.
The thermal performance of plastic packages is more dependent on the temperature
of the Printed Circuit Board to which the package is mounted. Again, if the
A
D
JA
JA
JC
CA
JC
= ambient temperature ˚C
= power dissipation in package
= package junction-to-case thermal resistance ˚C/W
is device-related and cannot be influenced by the user. The user controls the
= package junction-to-ambient thermal resistance ˚C/W
= package junction-to-ambient thermal resistance ˚C/W
= package case-to-ambient thermal resistance ˚C/W
DESIGN CONSIDERATIONS
T
R
J
JA
=
T
=
A
R
+
JC
P
D
+
R
SECTION
R
DSP56002/D, Rev. 3
CA
JA
J
, in C can be obtained from the
4
CA
. For
4-1